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Locascio A, Annona G, Caccavale F, D'Aniello S, Agnisola C, Palumbo A. Nitric Oxide Function and Nitric Oxide Synthase Evolution in Aquatic Chordates. Int J Mol Sci 2023; 24:11182. [PMID: 37446358 DOI: 10.3390/ijms241311182] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Revised: 07/03/2023] [Accepted: 07/04/2023] [Indexed: 07/15/2023] Open
Abstract
Nitric oxide (NO) is a key signaling molecule in almost all organisms and is active in a variety of physiological and pathological processes. Our understanding of the peculiarities and functions of this simple gas has increased considerably by extending studies to non-mammal vertebrates and invertebrates. In this review, we report the nitric oxide synthase (Nos) genes so far characterized in chordates and provide an extensive, detailed, and comparative analysis of the function of NO in the aquatic chordates tunicates, cephalochordates, teleost fishes, and amphibians. This comprehensive set of data adds new elements to our understanding of Nos evolution, from the single gene commonly found in invertebrates to the three genes present in vertebrates.
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Affiliation(s)
- Annamaria Locascio
- Department of Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn, Villa Comunale, 80121 Naples, Italy
| | - Giovanni Annona
- Department of Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn, Villa Comunale, 80121 Naples, Italy
- Department of Research Infrastructure for Marine Biological Resources (RIMAR), Stazione Zoologica Anton Dohrn, Villa Comunale, 80121 Naples, Italy
| | - Filomena Caccavale
- Department of Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn, Villa Comunale, 80121 Naples, Italy
| | - Salvatore D'Aniello
- Department of Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn, Villa Comunale, 80121 Naples, Italy
| | - Claudio Agnisola
- Department of Biology, University of Naples Federico II, Via Cinthia 4, 80126 Naples, Italy
| | - Anna Palumbo
- Department of Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn, Villa Comunale, 80121 Naples, Italy
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López JM, Morona R, González A. Pattern of nitrergic cells and fibers organization in the central nervous system of the Australian lungfish, Neoceratodus forsteri (Sarcopterygii: Dipnoi). J Comp Neurol 2019; 527:1771-1800. [PMID: 30689201 DOI: 10.1002/cne.24645] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Revised: 01/18/2019] [Accepted: 01/18/2019] [Indexed: 12/18/2022]
Abstract
The Australian lungfish Neoceratodus forsteri is the only extant species of the order Ceratodontiformes, which retained most of the primitive features of ancient lobe finned-fishes. Lungfishes are the closest living relatives of land vertebrates and their study is important for deducing the neural traits that were conserved, modified, or lost with the transition from fishes to land vertebrates. We have investigated the nitrergic system with neural nitric oxide synthase (NOS) immunohistochemistry and NADPH-diaphorase (NADPH-d) histochemistry, which yielded almost identical results except for the primary olfactory projections and the terminal and preoptic nerve fibers labeled only for NADPH-d. Combined immunohistochemistry was used for simultaneous detection of NOS with catecholaminergic, cholinergic, and serotonergic structures, aiming to establish accurately the localization of the nitrergic elements and to assess possible interactions between these neurotransmitter systems. The results demonstrated abundant nitrergic cells in the basal ganglia, amygdaloid complex, preoptic area, basal hypothalamus, mesencephalic tectum and tegmentum, laterodorsal tegmental nucleus, reticular formation, spinal cord, and retina. In addition, low numbers of nitrergic cells were observed in the olfactory bulb, all pallial divisions, lateral septum, suprachiasmatic nucleus, prethalamic and thalamic areas, posterior tubercle, pretectum, torus semicircularis, cerebellar nucleus, interpeduncular nucleus, the medial octavolateral nucleus, nucleus of the solitary tract, and the dorsal column nucleus. Colocalization of NOS and tyrosine hydroxylase was observed in numerous cells of the ventral tegmental area/substantia nigra complex. Comparison with other vertebrates, using a neuromeric analysis, reveals that the nitrergic system of Neoceratodus shares many neuroanatomical features with tetrapods and particularly with amphibians.
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Affiliation(s)
- Jesús M López
- Department of Cell Biology, Faculty of Biology, University Complutense of Madrid, Madrid, Spain
| | - Ruth Morona
- Department of Cell Biology, Faculty of Biology, University Complutense of Madrid, Madrid, Spain
| | - Agustín González
- Department of Cell Biology, Faculty of Biology, University Complutense of Madrid, Madrid, Spain
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Kumar P, Kasiviswanathan D, Sundaresan L, Kathirvel P, Veeriah V, Dutta P, Sankaranarayanan K, Gupta R, Chatterjee S. Harvesting clues from genome wide transcriptome analysis for exploring thalidomide mediated anomalies in eye development of chick embryo: Nitric oxide rectifies the thalidomide mediated anomalies by swinging back the system to normal transcriptome pattern. Biochimie 2015; 121:253-67. [PMID: 26717904 DOI: 10.1016/j.biochi.2015.12.013] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2015] [Accepted: 12/18/2015] [Indexed: 11/29/2022]
Abstract
Thalidomide, the notorious teratogen is known to cause various developmental abnormalities, among which a range of eye deformations are very common. From the clinical point of view, it is necessary to pinpoint the mechanisms of teratogens that tune the gene expression. However, to our knowledge, the molecular basis of eye deformities under thalidomide treatmenthas not been reported so far. Present study focuses on the possible mechanism by which thalidomide affects eye development and the role of Nitric Oxide in recovering thalidomide-mediated anomalies of eye development using chick embryo and zebrafish models with transcriptome analysis. Transcriptome analysis showed that 403 genes were up-regulated and 223 genes were down-regulated significantly in thalidomide pre-treated embryos. 8% of the significantly modulated genes have been implicated in eye development including Pax6, OTX2, Dkk1 and Shh. A wide range of biological process and molecular function was affected by thalidomide exposure. Biological Processes including structural constituent of eye lens and Molecular functions such as visual perception and retinal metabolic process formed strong annotation clustersindicating the adverse effects of thalidomide on eye development and function. Here, we have discussed the whole embryo transcriptome with the expression of PAX6, SOX2, and CRYAAgenes from developing eyes. Our experimental data showing structural and functional aspects includingeye size, lens transparency and optic nerve activity and bioinformatics analyses of transcriptome suggest that NO could partially protect thalidomide treated embryos from its devastating effects on eye development and function.
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Affiliation(s)
- Pavitra Kumar
- Vascular Biology Lab, AU-KBC Research Centre, Chennai, Tamil Nadu, India
| | - Dharanibalan Kasiviswanathan
- Vascular Biology Lab, AU-KBC Research Centre, Chennai, Tamil Nadu, India; Department of Biotechnology, Anna University, Chennai, Tamil Nadu, India
| | - Lakshmikirupa Sundaresan
- Vascular Biology Lab, AU-KBC Research Centre, Chennai, Tamil Nadu, India; Department of Biotechnology, Anna University, Chennai, Tamil Nadu, India
| | | | - Vimal Veeriah
- Vascular Biology Lab, AU-KBC Research Centre, Chennai, Tamil Nadu, India
| | - Priya Dutta
- Department of Biotechnology, Anna University, Chennai, Tamil Nadu, India
| | | | | | - Suvro Chatterjee
- Vascular Biology Lab, AU-KBC Research Centre, Chennai, Tamil Nadu, India; Department of Biotechnology, Anna University, Chennai, Tamil Nadu, India.
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López JM, Lozano D, Morona R, González A. Organization of the nitrergic neuronal system in the primitive bony fishes Polypterus senegalus and Erpetoichthys calabaricus (Actinopterygii: Cladistia). J Comp Neurol 2015; 524:1770-804. [PMID: 26517971 DOI: 10.1002/cne.23922] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Revised: 10/27/2015] [Accepted: 10/28/2015] [Indexed: 01/22/2023]
Abstract
Cladistians are a group of basal actinopterygian fishes that constitute a good model for studying primitive brain features, most likely present in the ancestral bony fishes. The analysis of the nitrergic neurons (with the enzyme nitric oxide synthase; NOS) has helped in understanding important aspects of brain organization in all vertebrates studied. We investigated the nitrergic system of two cladistian species by means of specific antibodies against NOS and NADPH-diaphorase (NADPH-d) histochemistry, which, with the exception of the primary olfactory and terminal nerve fibers, labeled only for NADPH-d, yielded identical results. Double immunohistochemistry was conducted for simultaneous detection of NOS with tyrosine hydroxylase, choline acetyltransferase, calbindin, calretinin, and serotonin, to establish accurately the localization of the nitrergic neurons and fibers and to assess possible interactions between these neuroactive substances. The pattern of distribution in both species showed only subtle differences in the density of labeled cells. Distinct groups of NOS-immunoreactive cells were observed in pallial and subpallial areas, paraventricular region, tuberal and retromammillary hypothalamic areas, posterior tubercle, prethalamic and thalamic areas, optic tectum, torus semicircularis, mesencephalic tegmentum, interpeduncular nucleus, superior and middle reticular nuclei, magnocellular vestibular nucleus, solitary tract nucleus, nucleus medianus magnocellularis, the spinal cord and amacrine cells in the retina. Large neurons in cranial nerve sensory ganglia were also labeled. The comparison of these results with those from other vertebrates, using a neuromeric analysis, reveals a conserved pattern of organization of the nitrergic system from this primitive fish group to amniotes, including mammals.
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Affiliation(s)
- Jesús M López
- Department of Cell Biology, Faculty of Biology, University Complutense, 28040, Madrid, Spain
| | - Daniel Lozano
- Department of Cell Biology, Faculty of Biology, University Complutense, 28040, Madrid, Spain
| | - Ruth Morona
- Department of Cell Biology, Faculty of Biology, University Complutense, 28040, Madrid, Spain
| | - Agustín González
- Department of Cell Biology, Faculty of Biology, University Complutense, 28040, Madrid, Spain
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Tooker RE, Vigh J. Light-evoked S-nitrosylation in the retina. J Comp Neurol 2015; 523:2082-110. [PMID: 25823749 DOI: 10.1002/cne.23780] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2015] [Revised: 03/05/2015] [Accepted: 03/23/2015] [Indexed: 01/14/2023]
Abstract
Nitric oxide (NO) synthesis in the retina is triggered by light stimulation. NO has been shown to modulate visual signal processing at multiple sites in the vertebrate retina, via activation of the most sensitive target of NO signaling, soluble guanylate cyclase. NO can also alter protein structure and function and exert biological effects directly by binding to free thiol groups of cysteine residues in a chemical reaction called S-nitrosylation. However, in the central nervous system, including the retina, this reaction has not been considered to be significant under physiological conditions. Here we provide immunohistochemical evidence for extensive S-nitrosylation that takes place in the goldfish and mouse retinas under physiologically relevant light intensities, in an intensity-dependent manner, with a strikingly similar pattern in both species. Pretreatment with N-ethylmaleimide (NEM), which occludes S-nitrosylation, or with 1-(2-trifluromethylphenyl)imidazole (TRIM), an inhibitor of neuronal NO synthase, eliminated the light-evoked increase in S-nitrosylated protein immunofluorescence (SNI) in the retinas of both species. Similarly, light did not increase SNI, above basal levels, in retinas of transgenic mice lacking neuronal NO synthase. Qualitative analysis of the light-adapted mouse retina with mass spectrometry revealed more than 300 proteins that were S-nitrosylated upon illumination, many of which are known to participate directly in retinal signal processing. Our data strongly suggest that in the retina light-evoked NO production leads to extensive S-nitrosylation and that this process is a significant posttranslational modification affecting a wide range of proteins under physiological conditions.
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Affiliation(s)
- Ryan E Tooker
- Department of Biomedical Sciences, Colorado State University, Fort Collins, Colorado, 80523
| | - Jozsef Vigh
- Department of Biomedical Sciences, Colorado State University, Fort Collins, Colorado, 80523
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Nitric oxide production and the expression of two nitric oxide synthases in the avian retina. Vis Neurosci 2013; 30:91-103. [PMID: 23721886 DOI: 10.1017/s0952523813000126] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Nitric oxide (NO) is known to exert multiple effects on the function of many retinal neurons and their synapses. Therefore, it is equally important to understand the potential sources of NO within the retina. To explore this, we employ a combination of 4-amino-5-methylamino-2',7'-difluorofluorescein diacetate (DAF-FM) based NO detection and immunohistochemistry for the NO synthetic enzymes, neuronal and endothelial nitric oxide synthase (nNOS and eNOS). We find DAF signals in photoreceptors, horizontal cells, amacrine cells, efferent synapses, Müller cells, and cells in the ganglion cell layer (GCL). nNOS immunoreactivity was consistent with the DAF signal with the exception that horizontal cells and Müller cells were not clearly labeled. eNOS-like immunoreactivity (eNOS-LI) was more widespread with photoreceptors, horizontal cells, occasional bipolar cells, amacrine cells, Müller cells, and cells in the GCL all showing labeling. Double labeling with antibodies raised against calretinin, syntaxin, and glutamine synthetase confirmed that horizontal cells, amacrine cells, and Müller cells (respectively) were expressing eNOS-LI. Although little or no nNOS labeling is observed in horizontal cells or Müller cells, the expression of eNOS-LI is consistent with the ability of these cells to produce NO. Together these results suggest that the capability to produce NO is widespread in the chicken retina. We propose that multiple forms of regulation for nNOS and eNOS play a role in the patterning of NO production in the chicken retina.
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Blom J, Giove T, Deshpande M, Eldred WD. Characterization of nitric oxide signaling pathways in the mouse retina. J Comp Neurol 2013; 520:4204-17. [PMID: 22592770 DOI: 10.1002/cne.23148] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Nitric oxide (NO) is a gaseous neuromodulator with physiological functions in every retinal cell type. NO is synthesized by several nitric oxide synthases (NOS) and often functions through its second messenger, cyclic guanosine monophosphate (cGMP), and protein kinase G (PKG). This study combined NO imaging, immunocytochemistry, biochemistry, and molecular biology to localize NO and its downstream signaling pathways in the mouse retina. Neuronal NOS (nNOS) was localized primarily in puncta in the inner plexiform layer, in amacrine cells, and in somata in the ganglion cell layer. Endothelial NOS was in blood vessels. Light-stimulated NO production imaged with diaminofluorescein was present in somata in the inner nuclear layer and in synaptic boutons in the inner plexiform layer. The downstream target of NO, soluble guanylate cyclase (sGC), was in somata in the inner and outer nuclear layers and in both plexiform layers. Cyclic GMP immunocytochemistry was used functionally to localize sGC that was activated by an NO donor in amacrine, bipolar, and ganglion cells. Cyclic GMP-dependent protein kinase (PKG) Iα was found in bipolar cells, ganglion cells, and both plexiform layers, whereas PKG II was found in the outer plexiform layer, amacrine cells, and somata in the ganglion cell layer. This study shows that the NO/cGMP/PKG signaling pathway is functional and widely distributed in specific cell types in the outer and inner mouse retina. A better understanding of these signaling pathways in normal retina will provide a firm basis for targeting their roles in retinal pathology.
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Affiliation(s)
- Jan Blom
- Department of Biology, Boston University, Boston, Massachusetts 02215, USA
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Thoreson WB, Mangel SC. Lateral interactions in the outer retina. Prog Retin Eye Res 2012; 31:407-41. [PMID: 22580106 PMCID: PMC3401171 DOI: 10.1016/j.preteyeres.2012.04.003] [Citation(s) in RCA: 136] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2012] [Revised: 03/05/2012] [Accepted: 03/09/2012] [Indexed: 10/28/2022]
Abstract
Lateral interactions in the outer retina, particularly negative feedback from horizontal cells to cones and direct feed-forward input from horizontal cells to bipolar cells, play a number of important roles in early visual processing, such as generating center-surround receptive fields that enhance spatial discrimination. These circuits may also contribute to post-receptoral light adaptation and the generation of color opponency. In this review, we examine the contributions of horizontal cell feedback and feed-forward pathways to early visual processing. We begin by reviewing the properties of bipolar cell receptive fields, especially with respect to modulation of the bipolar receptive field surround by the ambient light level and to the contribution of horizontal cells to the surround. We then review evidence for and against three proposed mechanisms for negative feedback from horizontal cells to cones: 1) GABA release by horizontal cells, 2) ephaptic modulation of the cone pedicle membrane potential generated by currents flowing through hemigap junctions in horizontal cell dendrites, and 3) modulation of cone calcium currents (I(Ca)) by changes in synaptic cleft proton levels. We also consider evidence for the presence of direct horizontal cell feed-forward input to bipolar cells and discuss a possible role for GABA at this synapse. We summarize proposed functions of horizontal cell feedback and feed-forward pathways. Finally, we examine the mechanisms and functions of two other forms of lateral interaction in the outer retina: negative feedback from horizontal cells to rods and positive feedback from horizontal cells to cones.
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Affiliation(s)
- Wallace B. Thoreson
- Departments of Ophthalmology & Visual Sciences and Pharmacology & Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE 68198 USA
| | - Stuart C. Mangel
- Department of Neuroscience, The Ohio State University College of Medicine, Columbus, OH 43210 USA
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Schmitz F, Natarajan S, Venkatesan JK, Wahl S, Schwarz K, Grabner CP. EF hand-mediated Ca- and cGMP-signaling in photoreceptor synaptic terminals. Front Mol Neurosci 2012; 5:26. [PMID: 22393316 PMCID: PMC3289946 DOI: 10.3389/fnmol.2012.00026] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2012] [Accepted: 02/15/2012] [Indexed: 12/11/2022] Open
Abstract
Photoreceptors, the light-sensitive receptor neurons of the retina, receive and transmit a plethora of visual informations from the surrounding world. Photoreceptors capture light and convert this energy into electrical signals that are conveyed to the inner retina. For synaptic communication with the inner retina, photoreceptors make large active zones that are marked by synaptic ribbons. These unique synapses support continuous vesicle exocytosis that is modulated by light-induced, graded changes of membrane potential. Synaptic transmission can be adjusted in an activity-dependent manner, and at the synaptic ribbons, Ca2+- and cGMP-dependent processes appear to play a central role. EF-hand-containing proteins mediate many of these Ca2+- and cGMP-dependent functions. Since continuous signaling of photoreceptors appears to be prone to malfunction, disturbances of Ca2+- and cGMP-mediated signaling in photoreceptors can lead to visual defects, retinal degeneration (rd), and even blindness. This review summarizes aspects of signal transmission at the photoreceptor presynaptic terminals that involve EF-hand-containing Ca2+-binding proteins.
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Affiliation(s)
- Frank Schmitz
- Department of Neuroanatomy, Medical School Homburg/Saar, Institute for Anatomy and Cell Biology, Saarland University Saarland, Germany
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Murphy MJ, Crewther DP, Goodyear MJ, Crewther SG. Light modulation, not choroidal vasomotor action, is a regulator of refractive compensation to signed optical blur. Br J Pharmacol 2011; 164:1614-26. [PMID: 21418189 PMCID: PMC3230809 DOI: 10.1111/j.1476-5381.2011.01347.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2010] [Revised: 01/19/2011] [Accepted: 02/02/2011] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND AND PURPOSE The nitric oxide system has two proposed sites and mechanisms of action within the ocular growth/refractive compensation platform-neuromodulatory effects on retinal physiology, and vascular/smooth muscle effects in the choroid. The relative contribution of these mechanisms are tested here with drugs that perturb the nitric oxide system and with slow flicker modulation of the ON and OFF pathways of the retina. EXPERIMENTAL APPROACH Intravitreal injection of saline or 900 nmol N(G) -nitro-L-arginine methyl ester or L-arginine in saline was followed by monocular defocus with ±10 D lens (or no lens), from days 5-9 under standard diurnal (SD) or daytime 1 Hz ramped flicker conditions. Biometric, electrophysiological and histological analyses were conducted. KEY RESULTS After 4 days of SD conditions, both drugs enhanced electroretinogram (ERG) b-wave cf. d-wave amplitudes compared with saline and reduced refractive compensation to -10 D lenses. Under flicker conditions compensation to +10 D lenses was suppressed. Choroidal thinning was observed in the drug, no lens groups under SD conditions, whereas choroidal thickening was seen in most groups under flicker conditions, irrespective of refractive outcomes. CONCLUSIONS AND IMPLICATIONS As choroidal thickness was not predictive of final refractive compensation across any of the variables of drug, defocus sign or light condition, it is unlikely that choroidal thickness is a primary mechanism underlying refractive compensation across the range of parameters of this study. Rather, the changes in refractive compensation observed under these particular drug and light conditions are more likely due to a neuromodulatory action on retinal ON and OFF pathways.
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Affiliation(s)
- Melanie J Murphy
- School of Psychological Science, La Trobe University, Melbourne, Victoria, Australia
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Jackman SL, Babai N, Chambers JJ, Thoreson WB, Kramer RH. A positive feedback synapse from retinal horizontal cells to cone photoreceptors. PLoS Biol 2011; 9:e1001057. [PMID: 21559323 PMCID: PMC3086870 DOI: 10.1371/journal.pbio.1001057] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2010] [Accepted: 03/25/2011] [Indexed: 12/31/2022] Open
Abstract
Cone photoreceptors and horizontal cells (HCs) have a reciprocal synapse that
underlies lateral inhibition and establishes the antagonistic center-surround
organization of the visual system. Cones transmit to HCs through an excitatory
synapse and HCs feed back to cones through an inhibitory synapse. Here we report
that HCs also transmit to cone terminals a positive feedback signal that
elevates intracellular Ca2+ and accelerates neurotransmitter
release. Positive and negative feedback are both initiated by AMPA receptors on
HCs, but positive feedback appears to be mediated by a change in HC
Ca2+, whereas negative feedback is mediated by a change in
HC membrane potential. Local uncaging of AMPA receptor agonists suggests that
positive feedback is spatially constrained to active HC-cone synapses, whereas
the negative feedback signal spreads through HCs to affect release from
surrounding cones. By locally offsetting the effects of negative feedback,
positive feedback may amplify photoreceptor synaptic release without sacrificing
HC-mediated contrast enhancement. Visual images are projected by the lens of the eye onto a sheet of photoreceptor
cells in the retina called rods and cones. Like the pixels in a digital camera,
each photoreceptor generates an electrical response proportional to the local
light intensity. Each photoreceptor then initiates a chemical signal that is
transmitted to downstream neurons, ultimately reaching the brain. But unlike the
pixels of a digital camera, photoreceptors indirectly inhibit one another
through laterally projecting horizontal cells. Horizontal cells integrate
signals from many photoreceptors and provide inhibitory feedback. This feedback
is thought to underlie “lateral inhibition,” a process that sharpens
our perception of contrast and color. Here we report the surprising finding that
horizontal cells also provide positive feedback to photoreceptors, utilizing a
mechanism distinct from negative feedback. The positive feedback signal is
constrained to individual horizontal cell–photoreceptor connections,
whereas the negative feedback signal spreads throughout a horizontal cell to
affect many surrounding photoreceptors. By locally offsetting negative feedback,
positive feedback boosts the photoreceptor signal while preserving contrast
enhancement.
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Affiliation(s)
- Skyler L. Jackman
- Department of Physics, University of California, Berkeley, Berkeley,
California, United States of America
| | - Norbert Babai
- Department of Ophthalmology, University of Nebraska Medical Center,
Omaha, Nebraska, United States of America
| | - James J. Chambers
- Department of Chemistry, University of Massachusetts, Amherst, Amherst,
Massachusetts, United States of America
| | - Wallace B. Thoreson
- Department of Ophthalmology, University of Nebraska Medical Center,
Omaha, Nebraska, United States of America
| | - Richard H. Kramer
- Department of Molecular and Cell Biology, University of California,
Berkeley, Berkeley, California, United States of America
- * E-mail:
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The light-induced reduction of horizontal cell receptive field size in the goldfish retina involves nitric oxide. Vis Neurosci 2011; 28:137-44. [PMID: 21324227 DOI: 10.1017/s0952523810000490] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Horizontal cells of the vertebrate retina have large receptive fields as a result of extensive gap junction coupling. Increased ambient illumination reduces horizontal cell receptive field size. Using the isolated goldfish retina, we have assessed the contribution of nitric oxide to the light-dependent reduction of horizontal cell receptive field size. Horizontal cell receptive field size was assessed by comparing the responses to centered spot and annulus stimuli and from the responses to translated slit stimuli. A period of steady illumination decreased the receptive field size of horizontal cells, as did treatment with the nitric oxide donor (Z)-1-[N-(2-aminoethyl)-N-(2-ammonioethyl)amino]diazen-1-ium-1,2-diolate (100 μM). Blocking the endogenous production of nitric oxide with the nitric oxide synthase inhibitor, N(G)-nitro-L-arginine methyl ester (1 mM), decreased the light-induced reduction of horizontal cell receptive field size. These findings suggest that nitric oxide is involved in light-induced reduction of horizontal cell receptive field size.
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Sato M, Ohtsuka T, Stell WK. Endogenous nitric oxide enhances the light-response of cones during light-adaptation in the rat retina. Vision Res 2010; 51:131-7. [PMID: 20951158 DOI: 10.1016/j.visres.2010.10.011] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2010] [Revised: 09/23/2010] [Accepted: 10/07/2010] [Indexed: 11/25/2022]
Abstract
The electroretinogram (ERG) is a non-invasive indicator of retinal function. Light flashes evoke a cornea-negative a-wave followed by a cornea-positive b-wave. Light-adaptation is known to increase the amplitude of cone-dependent b-waves. To identify the underlying mechanism, we recorded rat cone photoresponses in situ, using intravitreally-injected glutamate to block synaptic transmission and intense paired-flash stimuli to isolate cone a-waves. Steady adapting illumination caused a progressive increase in cone a-wave amplitude, which was suppressed in a dose-dependent manner by intravitreal CPTIO, a nitric oxide scavenger. We conclude that light-adaptation causes release of nitric oxide, which enhances the cone photoresponse.
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Affiliation(s)
- Masaki Sato
- Biology Research Division, Graduate School of Science, Toho University, 2-2-1 Miyama, Funabashi, 274-8510 Chiba, Japan
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